1. Field of the Invention
This invention relates to the care and maintenance of animals, such as rodents, for research purposes; and, more particularly, to cages and accessories facilitating the daily care of the animals.
2. Description of the Prior Art
It is important in research that animals being treated be maintained in a sanitary condition, since the results of the research often depend upon the prevention of the spread of disease among the animals. Such illness or death of the animals from extraneous causes could nullify a research project.
Cages for experimental animals, such as rodents, have been made partially of metal heretofore. The rodents frequently gnaw on the exposed portions on their cages or drinking nozzles, and with such cages cause ingestion of metal or the oxides of the metal to interfere with results of the tests, particularly in nutritional experiments. It is also important that the cages be constructed to allow proper ventilation.
A wide variety of different types of apparatus have been proposed including pans beneath the cages with rotary scrapers, permeable bottom cages with adsorbent paper that can be periodically pulled forward and disposed of, droppings on a belt having a rewind cable, egg collecting belts, perforate bottoms, experimental cages with electrical connectors for monitoring movement and cages with laterally movable "catch sheets" of polyethylene or the like. Automated water delivery systems have been proposed in which conduits having troughs that are float operated or otherwise operated, dispense water to the rodents or occupants of the cages. The expense of employing the special sheets of material or the risk of waste feeding through the material onto occupants of cages therebelow have prevented the completely satisfactory solution to the problem. Moreover, the systems that dispense at the whim of the operator were subject to a number of disadvantages, since it is desirable that drinking water and the like be dispensed on demand of the occupant within the cage, without running onto lower cages.
Thus, despite the wide variety of approaches tried in the prior art, no completely satisfactory approach has yet been found in allowing economically feasible collection of waste and readily refillable water containers.